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Alexandr
Asked:2020-04-06 00:45:17 +0000 UTC2020-04-06 00:45:17 +0000 UTC

拖放 WPF

  • 772

请告诉我哪里出了问题。我想使用拖放插入图片，但拖动后我得到Image一个属性Source等于 null的对象

XAML 

    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="300"></ColumnDefinition>
        <ColumnDefinition Width="*"></ColumnDefinition>
    </Grid.ColumnDefinitions>
    <ScrollViewer Grid.RowSpan="2">
        <StackPanel CanVerticallyScroll="True">
            <Image Source="Resources/part1.jpg" Width="280" Height="121" Margin="0,10,0,10" MouseDown="Image_MouseDown" Stretch="UniformToFill"/>
            <Image Source="Resources/part2.jpg" Width="280" Height="121" Margin="0,10,0,10" MouseDown="Image_MouseDown" Stretch="UniformToFill"/>
            <Image Source="Resources/part3.jpg" Width="280" Height="121" Margin="0,10,0,10" MouseDown="Image_MouseDown" Stretch="UniformToFill"/>
            <Image Source="Resources/part4.jpg" Width="280" Height="121" Margin="0,10,0,10" MouseDown="Image_MouseDown" Stretch="UniformToFill"/>
            <Image Source="Resources/part5.jpg" Width="280" Height="121" Margin="0,10,0,10" MouseDown="Image_MouseDown" Stretch="UniformToFill"/>
            <Image Source="Resources/part6.jpg" Width="280" Height="121" Margin="0,10,0,10" MouseDown="Image_MouseDown" Stretch="UniformToFill"/>
        </StackPanel>
    </ScrollViewer>
    <Canvas Grid.Column="1" Margin="0,0,0,0" >
        <Image Source="Resources/part1.jpg" Width="280" Height="120" Drop="Image_Drop" DragEnter="Image_DragEnter" AllowDrop="True" Stretch="UniformToFill" Canvas.Left="156" Canvas.Top="51"/>
        <Image Source="Resources/part2.jpg" Width="280" Height="120" Drop="Image_Drop" AllowDrop="True" Stretch="UniformToFill" Canvas.Left="436" Canvas.Top="51"/>
        <Image Source="Resources/part3.jpg" Width="280" Height="120" Drop="Image_Drop" AllowDrop="True" Stretch="UniformToFill" Canvas.Left="156" Canvas.Top="170"/>
        <Image Source="Resources/part4.jpg" Width="280" Height="120" Drop="Image_Drop" AllowDrop="True" Stretch="UniformToFill" Canvas.Left="436" Canvas.Top="170"/>
        <Image Source="Resources/part5.jpg" Width="280" Height="120" Drop="Image_Drop" AllowDrop="True" Stretch="UniformToFill" Canvas.Left="156" Canvas.Top="288"/>
        <Image Source="Resources/part6.jpg" Width="280" Height="120" Drop="Image_Drop" AllowDrop="True" Stretch="UniformToFill" Canvas.Left="436" Canvas.Top="288"/>
    </Canvas>

</Grid>

C＃

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    private void Image_Drop(object sender, DragEventArgs e)
    {
        ((Image) sender).Source = e.Source as ImageSource;
    }

    private void Image_MouseDown(object sender, MouseButtonEventArgs e)
    {
        // sender – объект, на котором произошло данное событие.
        Image lbl = sender as Image;
        // Создаем источник.
        // Копируем содержимое метки Drop.
        // 1 параметр: Элемент управления, который будет источником.
        // 2 параметр: Данные, которые будут перемещаться.
        // 3 параметр: Эффект при переносе.
        DragDrop.DoDragDrop(lbl, lbl.Source, DragDropEffects.Copy);
    }

    private void Image_DragEnter(object sender, DragEventArgs e)
    {
        e.Effects = DragDropEffects.Copy;
    }
}

git 链接https://github.com/Sechik/Puzzle

c#

1 个回答

  1. Best Answer

    您的来源不同（您正在尝试分配它们）：

    {pack://application:,,,/Puzzle;component/Resources/part3.jpg}
{System.Windows.Controls.Image}

    这就是复制发生的方式，但图片在sender和e

    private void Image_Drop(object sender, DragEventArgs e)
    {
        //((Image) sender).Source = e.Source as ImageSource;

        Image image = e.Source as Image;

        ((Image)sender).Source = image.Source;
    }

    这是一个现成的解决方案（这里的图片是通过额外的变量传递的）：

    using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace Puzzle
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public static Image global_sender;
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Image_Drop(object sender, DragEventArgs e)
        {
            //((Image) sender).Source = e.Source as ImageSource;

            //Image image = e.Source as Image;

            //((Image)sender).Source = image.Source;

            ((Image)sender).Source = global_sender.Source;
        }

        private void Image_MouseDown(object sender, MouseButtonEventArgs e)
        {
            // sender – объект, на котором произошло данное событие.
            Image lbl = sender as Image;
            global_sender = lbl;
            // Создаем источник.
            // Копируем содержимое метки Drop.
            // 1 параметр: Элемент управления, который будет источником.
            // 2 параметр: Данные, которые будут перемещаться.
            // 3 параметр: Эффект при переносе.
            DragDrop.DoDragDrop(lbl, lbl.Source, DragDropEffects.Copy);

        }

        private void Image_DragEnter(object sender, DragEventArgs e)
        {
            e.Effects = DragDropEffects.Copy;
        }
    }
}

    在此处输入图像描述

    • 4

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